1. Field of the Invention
The present invention relates to a mounting device, and more particularly to a mounting device for chips, which incorporates a heat sink on which the chips are mounted.
2. Description of the Prior Arts
In the electronics industry, heat sinks are generally used on electronic components to dissipate heat generated by processing units. Many kinds of conventional mounting devices are used to mount chips on a heat sink.
With reference to FIG. 13, a conventional mounting device for a chip in accordance with the prior art comprises a chip unit (71), an insulated gasket (72), a heat sink (73) and a fastener (74). The chip unit (71) comprises a chip and a mounting tab. The chip has a rear surface. The mounting tab is attached to and protrudes up from the rear surface of the chip and has an upper end, a rear surface and a mounting hole (711). The mounting hole (711) is formed through the mounting tab near the upper end. The insulated gasket (72) is mounted against the rear surface of the mounting tab and has a mounting hole (721) and a rear surface. The mounting hole (721) is formed through the insulated gasket (72) and corresponds to and aligns with the mounting hole (711) in the mounting tab. The heat sink (73) is mounted against the rear surface of the insulated gasket (72) and has a mounting hole (731). The mounting hole (731) is formed through the heat sink (73) and corresponds to and aligns with the mounting hole (721) in the insulated gasket (72). The fastener (74) is mounted through the mounting holes (711, 721, 731), connects the chip unit (71), the insulated gasket (72) and the heat sink (73) together and comprises a collar (742), a bolt (741), multiple washers (743) and a nut (744). The collar (742) is mounted through the mounting holes (711, 721, 731). The bolt (741) is mounted through the collar (742). The washers (743) are mounted around the bolt (741) against the collar (742) and the heat sink (73). The nut (744) screws onto the bolt (741) to hold the chip unit (71), the insulated gasket (72) and the heat sink (73) together. However, assembling the conventional mounting device takes a lot of time because components of the fastener (74) are small and tedious to install and connect. Moreover, the conventional mounting device is unsteady when used with high voltage. Because the chip unit (71) is so close to the bolt (741), voltage differential between the chip unit (71) and the bolt (741) is too high and may cause insulation breakdown or a flashover that will damage the chip unit (71).
With reference to FIG. 14, another conventional mounting device in accordance with the prior art mounts multiple chip units (71A) on a heat sink (73A) and comprises multiple insulated covers (76), a brace (78) and multiple bolts (75). The insulated covers (76) are resilient and are mounted respectively on the chip units (71A). The brace (78) may be a flat bar, is connected to the heat sink (73A), is mounted against the chip units (71A) and holds the chip units (71A) against the heat sink (73A). This mounting device also takes a lot of time to assemble because the insulated covers (76) must be mounted on the chip units (71A) to prevent the chip units (71A) from being pressed with unequal pressures by the brace (78).
With reference to FIG. 15, another conventional mounting device in accordance with the prior art to mount a chip unit (71B) on a heat sink (73B) is a clamping device (77). The clamping device (77) has two ends, a protruding segment and a resilient clamp (771). The two ends are attached securely to the heat sink (73B). The protruding segment is U-shaped and holds a chip unit (71B) against the heat sink (73B). The resilient clamp (771) is an L-shaped tab, is formed on the protruding segment of the clamping device (77) and presses the chip unit (71B) against the heat sink (73B). This kind of mounting device is inconvenient and expensive to use in large volume applications because each clamping device (77) holds only one chip unit (71B).
To overcome the shortcomings, the present invention provides a mounting device to mitigate or obviate the aforementioned problems.